Sava Penkov
Berlinskii͡a︡t dogovor i Balkanite- Berlinskii︠a︡t dogovor i Balkanite
- Borbata na bǔlgarskiia narod protiv Berlinskiia dogovor ..
- Borbata na bŭlgarskii︠a︡ narod protiv Berlinskii︠a︡ dogovor i mezhdunarodnoto pravo, 1878-1886
- Bulgaria and the struggle against racial discrimination
- Bulgarian scientists against the neutron bomb
- Mezhdunarodni dogovori na Bŭlgarii︠a︡, 681-1947 g.
- Mezhdunarodni dogovori na Bŭlgarii͡a︡
- Mezhdunarodnopravni problemi na razorŭzhavaneto
- Rasovata diskriminat︠s︡ii︠a︡ i mezhdunarodnoto pravo